Ultra short wave amplifier



April 15, 1941. E. RAHN ULTRA SHORT WAVE AMPLIFIER Filed April 19, 19595 OUR@ E VAA .Jin

INVEN TOR. ERA/$7' QHN ATTORNEY.

Patented Apr. l5,` 1941 ULTRA snoR'r WAVE `AivfrnIFlEn Ernst Rahn,Berlin, Germany, assignor to Telefunken Gesellschaft fr DrahtloseTelegraphie, Berlin, Germany, a. corporation of Germany ApplicationApril 19, 1939,seri'a1Notasms Y i In Germany May 13,1938l n Claims.(Cl."17^9,1*7l) 'come known for various ultra short wave circuits.

The novelty relates to an arrangement for the amplication of ultra shortwaves by means of triodes. Circuit arrangements are known as such inwhich a tube with grid connection on two sides and plate connection ontwo sides is so connected with outer circuits that the grid-anode'capacity is compensated by a parallel inductance and that between thecathode and the anode an output circuit is placed, and between the gridand cathode an input circuit. The bringing out, at two sides, of thegrid and anode eliminates coupling between the individual circuits.However, it was found that in the case of decimeter Waves the knownarrangement does not permit of stable conditions of amplification andthat disturbances still appear which render the operating safetydoubtful.

'Ihe novelty of the present invention is based upon an appreciation ofthe fact that these disturbances, despite all the precautionarymeasures,

are due to a still existing coupling of the individual circuits acrossthe common part of the cathode lead-in, so that no coupling does existbetween the input circuit and output circuit and uncontrollableconditions of feed back 'and counter coupling are present.

In accordance with the present invention the said diiculties areovercome by employing means to render impossible a coupling of thecircuits across the common cathode lead. Such means include providingthe cathode as well as the other electrodes with connections at twosides, so that the grid-cathode circuit can be placed at the oneconnection point of the cathode, and the cathode-anode circuit at theother connection point. A

Figs. 1 and 2 show two embodiments of the present invention.

The tube structure as shown in Fig. 1 is singleended (incontradistinction to the push-pull type) and is entirely coaxial. y ItemK represents the cathode, G is the grid, and A is the anode, wherebyrespectively towards opposite sides of the tube double electrodeconnections are provided. 'I'he input circuit is designated by E, theoutput circuit is O, the compensation circuit for the grid-anodecapacity is designated by L, shown in this instance connected betweenthat terminal of the grid opposite the input circuit and that terminalof the anode opposite the output circuit.

In place of the bringing out of the cathode on two sides or in additionthereto, it is also possible to provide a tuning of the cathode lead byinserting a tunable circuit such as has already be- 'the heating lines.

Such a'tuninglikewise leads to avoiding the inuenceofdivsturbingcouplings through the common cathodeline. y

g'lhetuned cathode circuit has no bearing on The latter may, moreover,be choked or may be blocked as regards high frequency by insertingblocking circuits. Preferably, the tuned cathode circuit as well as theblocking circuits for the heating line are designed as tunable coaxiallines. Such an arrangement .is shown in Fig. 2 which does not requireany further explanation.

What is claimed is:

1. An ampliner for ultra short waves comprising an electron dischargedevice having anode, cathode and grid electrodes enclosed Within anenvelope, each of said electrodes having terminals extending throughopposite sides of said envelope, a source of heating energy for saidcathode,and a pair of leads from said sourceto opposite terminals ofsaid cathode, an input circuit coupled between the grid and cathodeterminals on one side of said envelope, and an output circuit coupledbetween the anode and cathode terminals on the opposite side of saidenvelope, and means for neutralizing the capacity coupling between inputand output circuits resulting from inherent capacity between grid andanode, said means being independent of both said input and outputcircuits and comprising a reactance coupled between one terminal of saidgrid and one terminal of said anode.

2. An amplifier for ultra short waves com- I prising an electrondischarge device having anode, cathode and grid electrodes enclosedwith- 1n an envelope, each of said electrodes having terminals extendingthrough opposite sides of vsaid envelope, an input circuit coupledbetween the grid and cathode terminals ori-one lside of said envelope,and an output circuitfcoupled between the anode and cathode terminals onthe opposite side of said envelope, and means for neutralizing thecapacity coupling between input and output circuits resulting frominherent capacity between grid and anode, said means comprising acapacitive connection from one vend of said grid to the oppositelylocated end of said anode. l

3. l An amplifier for ultra short waves comprising an electron dischargedevice having anode,

cathode and grid electrodes enclosed Within an that end of the anodewhich is opposite the vout-v` put circuit. g n n 4. A high frequencysystem comprising an electron discharge device h'aving'anode, cathodeand grid electrodes enclosed within an envelope, each of said electrodeshaving terminals Yextending through opposite sides of said envelope, aninput circuit coupled between the grid and cathy ode terminalson'bneside ofsaicl envelope, and

an output circuit coupled between the anode and cathode terminals on theopposite side of said envelope, and'means for neutralizing the capacityVVcathode, and a `pair of connections from said coupling between inputand output circuits resulting from inherent capacity between grid andanode, said means comprising a capacitive connection from one end ofsaid grid to the oppositely located end of said anode.

5. A high frequency single ended circuit comprising an electrondischarge device having anode, cathode and grid electrodes enclosedWithin lan envelope, each of said electrodes having terminals extendingthrough opposite sides of said envelope, a source of heating energy forsaid cathode, and a pair of leads from said source to opposite terminalsof said cathode, an input circuit coupled between the 'grid and cathodeterminals on one side of said envelope, and an output circuit coupledbetween the anode and cathode terminals on the opposite side of saidenvelope, and means for neutralizing the capacity coupling between inputand output circuits resulting from inherent capacity between grid andanode, said means being independent of both said rinput and outputcircuits and comprising a reactance coupled between one terminal of saidgrid and one terminal of said anode.

ERNST RAHN.

